Electric switch



Aug. 4, 1925. 1,548,799

' J. D. HILLIARD ELECTRIC SWITCH Filed Aug. l0. 1921 2 Sheets-Sheet 1Fig. 1. vm.'

Lm EL $9 m Inventor:

. John, D. Hilliard,

His Httorneg.

Ang. 4, 1925. 1,548,799

J. D. HILLIARD ELECTRIC SWITCH Filed Aug. 1o, 1921 2 Shaver-sneu a123.2. Fig.

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Patented Aug. 4, 1925.

UNITED STATES l 1,548,799 PATENT QFFICE.

JOHN D. HILLIARD, F SCHENECTADY, NEW YORK, ASSIGNOR TO GENERAL ELECTRICCOMPANY, A CORPORATION OF NEW YORK.

ELECTRIC 'swmcl f Appiication mea Angustia, 1921. serial 151. 491,127.

To aZZ'fwzom z't may concer/n.:

Be it known that I, J orrN D. HILLIARD, a citizen of the United States,residing at Schenectady, in the county of Schenectady, State of NewYork, have invented certain new and useful Improvements in ElectricSwitches, of which' the following is a specification. i

My invention'relates to electric switches and particularly to those inwhich the con-I tacts are separable in an insulating fluid. In switchesof this type heretofore employed use has been made of means whereby thepressure produced by the arc at the opening of the switch is utilized tocreate a blast of oilwhich is directed into the path of the arc andserves to extinguish the same. According to my present invention I seekto improve the circuit vinterrupting capacity of .switches of thischaracter by providing a plurality of breaks so arranged that thepressure produced by the arc 'at one of the breaks serves to force oilor other insulating fluid into the path of the arc at another of Thisoil not only serves to cool the gases of the second arc and so aid inextinguishing the same but also replaces thev arc gases by a body ofoil* Which, interposed in the circuit, offers an extremely highresistance to the further passage of current. By having the arc which itis intended to use as a source of pressure form ata point somewhatdistant from the second arc, the hot gases of the former may be kept,away from the latter and thus there is no tendency for thesel gases tolower the dielectric strength of the medium .surrounding the secondbreak or tomaintain the gases of the second arc at a high temperature.

In the preferred embodiment of my invention I draw the arc which is tobe subjected to the stream or blast of oil through a narrow passagewhich not only limits the quantity of gas formed but also by restrictingthe area of the arc 'stream increases its resistance;`

Othen advantages and objects of the invention will appear from thefollowing description taken in' connection with the accompanying drawingwherein Fig.I 1 shows a switch partly in section embodying my invention;and Figs. 2 and 3 are' views partly in section of a portion of theswitch similar to that shown in Fig. 1 but embodying a modifiedl form ofmy invention. v

InFig. 1 I have shown a switch comprisinga metallic vessel 10 adapted tocontain an insulating flui-d such as oil. Extending into the tank orvessel 10 are bushings 11 provided with suitable terminals 12 to whichthe circuit to be controlled is connected. Supported upon each bushingand depending therefrom below the normal surface of the insulating fluidis a vessel or chamber 13. These chambers are so' constructed as `'towithstand the considerable 'internal pressure and are well insulated bymeans of the bushings 11 from the vessel 10. vAt one end of` eachchamber is mounted a fixed contact 14 and movable into and out of theother end of each chamber is a movable contact 15 which as shownconsists of a rod carried at an end of and movable with a bridgingmember 17 vwhich latter is supported and movable by means of a rod 18 towhich any suitable operating fmechanism, not shown,

may be attached. Contact rod 15 moves` ing bushing 20. 'Mountedl uponthe bushing 420-bv means of rods 21 are insulated plates 22 which arespaced apart and are provided at their centers with alined openings 23through which the rod 15 is adapted to pass. Rod 15 is designed tocooperate with a con tact 2/1 formed at the lower end of the conductingmember 25. This member is mounted to move in an insulating bushing 26which is `supported by means of a perforated plate 27. Seated in arecess 28 in the insulating bushing 26 is a compression spring 29 whichbears at its lower end against the member 25. The upper end of themember 25 is formed with a contact 25 adapted to c0- operate with acontact 14 at the lower end of the terminal 12. ,I In practice when theswitch is opened the first break occurs at the contacts 14 and 25', thespring 29 serving to maintain the member 25 in contact with the rod 15during the downward movement of the latter until the lower face of thecontact 24 strikes the u per plate 22. 'During this initial part of t eoperation an arc is drawn between the contacts 14 and 25 which bydissociation and vaporization of the oil creates a high preswithdrawalof the rod through the open ing 19 results in the formation of a secondarc between the rod and Contact 24. Oil under the influence of thepressure created by the first formed arc in seeking an exit from thechamber 13 flows between the plates 22 and around the rod 15 as itrecedes through the opening 19. It will be thus seen that a body of cooloil unmixed with gases is proiected into the path of the lower are withthe result that the same is quickly extinguished.

If desired, there may be substituted for the rod 15 a tube open at itsupper end and at some point near its attachment to the bridging member17. It is preferable in this case that the tube be constructed to itrather closely in the bushing 2() so that the oil which is ejected fromthe chamber 13 will be forced to pass down the center of the tube.

I provide a small opening through the wall of the pressure chamber topermit the slow escape of gases which collect at the top of the chamber.

In the form of invention shown in Fig. 2 the rod 15 extends through thelength of the compression chamber and cooperates at its upper end withthe contact 14. In place of the insulating bushing 26 of Fig. 1 Iprovide a conducting member 31 through Y which the rod 15 moves andwhich is supported by means of the perforated insulating plate 33. Acontact '34 at'the lower end of the member 31 serves to insureelectrical connection between the rod 15 and member 31 while the rod iswithin the member and serves as an arcing electrode after the rod in itsdownward movement has left the member 31. The passage 37 in the member31 through which the rod 15 operates is formed with an enlargement at 35to containY a ball 36 which is adapted to close the passage upon thewithdrawal of the rod.

In the ,operation of the form of my in- '.vention shown in Fig. 2 theinitial or pressure producing arc is formed between the contact 14 androd 15. As the upper end of this rod is drawn below the upper end ofmember 31 this arc is transferred from the rod to the conducting member31. A further lowering of the rod 15 permits the ball 36 to seat itselfcentrally of the passage 37 and prevent any gases being forced-downwardly through the member 31. In the final movement of the rod 15its upper end leaves the contact 34 and forms a second arc which isdrawn downwardly through a restricted passage 38 in the bushing 39. Oilunder the pressure created byy the upper arc is forced through therestricted passage 38 and serves to extinguish the lower arc andconsequently break the circuit. In the upper part of the pressurechamber I preferably provide a hood 40 which serves to retain a portionof the gases formed within the chamber. This acts as a cushion andprevents toosuddenl a rise of pressure within the chamber and aconsequent shock to the apparatus. 'If desired, I may dispense with theball 36 in which case the passage 37 will be'formed without theenlargement 35.

The form ofmy invention shown in Fig. 3 is similar to that of Fig. 1 inthat use is made of an intermediate conducting member 25 which isadapted to form contact at its upper end with the stationary electrode14 and at its lower end with the movable conducting rod 15 and isspringpressed away from the electrode 14. In the form shown in Fig. 3,however, the lower portion of the intermediate conducting member-25moves freely in a recess 44 formed in -a specially constructed insulating member or bushing 42 which latter is supported from the bottom ofthe pressure chamber 43. Connecting with-the bottom of the recess 44 isan opening 45 through which the rod 15 moves and arranged at ri ghi'.angles to the opening 45 and crossing the saine are a plurality ofpassages 46 each of which communicates at one end with a longitudinalpassage 47 and at the other end with the interior of the vessel 10'a't apoint outside of the chamber 43. The passage 47 communicates at itsupper end with the interior of the chamber 43, In the closed position ofthe switch the presence of the rod 1,5 in the opening 14 serves to cutolf communication through the passages 46. The chamber 43 is providedwith a gas-collecting hood 40 similar to that shown in Fig. 2.

In operation the initial arc is drawn between the contact 14 andconducting member 25 which causes a very high pressure to be developedwithin the chamber 43. When the lower end of the member 25 reaches thebottom of the recess 44 it is stopped by the insulator 42 and thefurther downward movement of the rod 15 results in the drawing of thesecond arc through the opening 45, passages 46 are opened in successionand oil under the iniiuence of the pressure within the chamber 43 isprojected with great force across the arc in a direction at right anglesthereto and extinguishes the same. 1

lVhat I claim as new and desire to secure by Letters Patent of theUnited States is:

1. In a switch, a tank adapted to contain an insulating fluid, a vesseltherein, cooperating contacts arranged to form two arcs in series insaid vessel, and means whereby the fiuid under the pressure created byone of said arcs is directed intosthe path of the other arc. y

'2. In a switch, a tank adapted to contain CII mesme aninsulating'iluid, a pressure resisting vessel within said tank, aplurality of sets of relatively movable contacts in said vesselcqnnected in series and adapted when separated to draw arcs in saidfluid, and means for directing fluid expelled by one ofv said arcs intothe path of another of said arcs.

3. In a switch, a tank adapted-to contain an insulating liquid, apressure resisting vessel in said tank, a single contact operatingmember extending into said vessel, two pairs of contacts separablewithin said insulating liquid to draw arcs in succession, and meanswhereby a portion of saidrliquid under influence of the pressure createdby the first drawn arc, is forced into the path of the second drawn arc.p

4. In a switch comprising a vessel containing a body of insulatingliquid, means for forming an arc in said insulating liquid, meansforming a restricted passage in said liquid, means for forming a secondarc in said restricted passage and means whereby pressure created bysaid first formed arc will force liquid from said body of insulatingliquid through said restricted passage in the path of said second arc.

5. In a switch, an outer vessel adapted to contain an insulating liquid,an inner vessel adapted to be immersed in said insulating liquid and tocontain insulating liquid, means for forming two arcs in successionwithin said innervessel and means whereby pressure created by firstformed arc, .forces insulating liquid into the path of said secondformed arc and out of said inner vessel.

6. In a switch, an outer vessel adapted to contain an insulating liquid,an innervessel adapt-ed to be immersed in said insulating liquid and'tocontain insulating liquid, said inner vessel having a restricted passagethrough the wall thereof', means for forming an arc Within the innerVessel, means for subsequently :forming a second arc within saidpassage, and means whereby pressure created by the first formed arcforces insulating liquid through said assage. y

7. In a switch, a vessel a apted to contain ,insulating fluid, a.stationary electrode within the said vessel, a movable-electrode, anintermediate conducting member within said vessel adapted to form an arcwithin said fluid with each of said electrodes and means wherebyinsulating fluid under he influence of pressure created by one of saidarcs is forced into the path of the other of said arcs.

8. In a switch, a vessel adapted to contain insulating fluid, and formedwith a restricted passage, a stationary electrode within said vessel, amovable electrode, an intermediate conducting member within said vesseladapted yto form an arc within said fluid wit-heach of said electrodes,one of said arcs being formed in said restricted passage, and

means whereby insulating fluid under pressure created by the other ofsaid arcs is forcedV through said restricted passage.

9. In a switch, an outer vessel, an inner vessel adapted to contain andto be im.- mersed in insulating liquid contained within said outervessel, a stationary electrode within said inner vessel, E1n electrodemovable into and out of said inner vessel, an intermediate conductingmember biased away from said stationary and towaid said ii'iovableelectrode whereby upon movement -ot' said movable electrode away fromsaid stationary electrode, an arc is drawn between s`aid stationaryelectrode and conducting member, and means for limiting the y movementof said conducting member away from said stationary electrode, whereby yupon further movement of said movable electrode away from saidVstationary electrode, an arc is dra-wn between said conducting memberand movable 'electrode and means whereby pressure created by said firstfoi-ined are forces insulating liquid into the' 'path ot' said secondformed arc.

10. In a switch, a vessel adapted to contain an insulating fluid, astationary electrode within said vessel, a movable electrode adapted tomake contact with the said stationary electrode, a conducting membervsur-y rounding said movable electrode and so arranged that uponwithdrawal of said inevable electrode away from said stationaryelectrode, an arc is first` formed between said stationary and movableelectrodes which is subsequently transferred from said movable electrodeto said conducting' meinbei and finally a. second arcis drawn betweensaid movable electrode and conducting member and means whereby liquidunder the influence of pressure created by of said second formed arc.

. Y 11. In a switch, a vesseladapted to contain an insulating fluid andformed withA a restricted passage, a stationary electrode within saidvessel, a movable electrode adapted to make contact with said stationaryelcctrode, a conducting member surrounding said movable electrode and soarranged that upon withdrawal 'of said movable electrode away from saidystationary electrode an arc is first 'formed between said stationaryand movable electrodes which arc is subsequently transferred from saidmovable electrode .to said conducting member and finally a second arc isdrawn within said yrestricted passage and meanswhereby insu-

